1. Technical Field
The present invention relates to decoding systems and methods and more particularly to low-density parity-check codes which employ less information but provide improved performance.
2. Description of the Related Art
With capacity approaching decoding performance, low-density parity-check codes (LDPC) have drawn significant interest in many industries for the transmission of digital information, including cellular systems, digital recording systems, etc. While turbo codes have been adopted in 3G cellular standards, LDPC codes have been included in the IEEE 802.16 standard and also considered for potential application beyond 3G cellular standards, e.g., in 4G systems. Beside cellular systems, LDPC is also considered in digital video broadcasting (DVB) systems.
When applied to different systems, the requirements for decoding complexity and decoding throughput for LDPC codes are different. Soft decoding provides capacity approaching performance but has related high decoding complexity. The binary message-passing decoding (or Hard decoding), although it incurs some performance loss, has very low-complexity and high decoding throughput. Existing binary decoding algorithms include a majority decoding algorithm (i.e., time-invariant decoding, e.g., Majority Based (MB) decoding), and switch type decoding (e.g., Gallager decoding algorithm B (GB)) (time-variant decoding). These existing binary decoding methods require the degree information of variable nodes. To make the degree information available to the decoder, much additional complexity is introduced on a circuit implementation of the LDPC decoder.
Therefore, a need exists for a new binary message-passing LDPC coding that does not need degree information and provides the same or better performance than existing systems.